Chemical-free Gardens

Lawns aren’t the only place where home gardeners use a lot of herbicides. Glyphosate, the active ingredient in many commercial weed killers designed for ornamental beds, ranks second only to 2,4-D in number of pounds sold annually in the United States for home and garden use.

“Glyphosate may at first glance seem less toxic than other pesticides,” says Leo Trasande, MD, MPP, an environmental pediatrician at the Mount Sinai School of Medicine in New York. But he points out that some of the so-called inert ingredients in commercial formulations can make the products more toxic than glyphosate alone. And he adds that the chemical can be fatal when ingested—no small concern in a household with children. A 2002 Swedish study also found an association between glyphosate herbicide use and non-Hodgkin’s lymphoma (Leukemia and Lymphoma, vol. 43, no. 5). “There are health concerns to keep in mind in using any pesticide,” says Trasande.

As with a lawn, alternatives can be healthier for your soil and your flowers, shrubs, and trees. Here are some options to consider.

Mulch. Mulch is the first line of defense against weeds in an ornamental bed, according to Tim Gilpin, PhD, an environmental chemist and the owner of an organic lawn-care company in Boulder, Colorado—and mulch also adds a healthy dose of organic matter to the soil. Gilpin likes to hand-pick weeds that do emerge. The ones that make it through the mulch “tend to be spindly and easy to pick when they do pop up,” Gilpin says.

Vinegar. That’s right—if you want to weed without bending over, says Gilpin, an organic option may already be sitting in your kitchen cupboard: household vinegar. Realize that like glyphosate-containing herbicides, vinegar can injure or kill whatever plant it contacts, including grass, so be careful where you apply it. And Gilpin points out that whether you use glyphosate or vinegar, “weeds look ugly after you spray them.” You can use straight household vinegar, but Gilpin has seen better results when he mixes in about 10 percent dish soap to help the vinegar coat the leaves. To apply, spray the vinegar on, wetting leaves, preferably on a hot, sunny day. USDA research suggests that vinegar works best on weeds less than two weeks old. Because it doesn’t kill roots, you may need to reapply it. Note that premixed vinegar herbicides with acetic-acid concentrations much higher than the 5 percent of household vinegars can burn skin and eyes.

Weeding tools. If you like gadgets, some of the new tools on the market might suit you. Some enable you to pop weeds out of the ground without bending over, while others use flames or radiant heat to kill weeds. Check them out at your local nursery.